1. Technical Field
This invention concerns to a spark plug incorporating a pressure sensor.
2. Related Art
It is important to be aware of the pressure inside the cylinders of an internal combustion engine. By knowing this, it becomes possible to maintain better control of combustion in the engine. This better control in turn makes it possible to limit fuel consumption and also to have an engine that produces fewer pollutants. In gasoline engines, a pressure sensor measuring the existing pressure in the cylinders also makes it possible to avoid the need for a knock detector.
Several solutions of the prior art exist for integrating a sensor in order to enable measurement of the pressure existing in a cylinder of engine gasoline. For example, a pressure sensor may be placed in the cylinder. However, this necessitates modification of the cylinder head to allow the sensor to pass through. Measurement of the pressure existing in a cylinder by measuring the deformation of the cylinder head is also known. This solution also requires that the cylinder head of the engine be adapted and also has the disadvantage of being very difficult to calibrate.
Mounting of a sensor on the plug spark is also known, for example, as shown in U.S. Pat. No. 6,756,722. The disadvantage of the solution suggested in this patent document is that the sensor is obstructed and the assembly proposed is complex. Moreover, the sensor disclosed in this document works on compression.